Method, apparatus, and system for detecting transmitter approximating or touching touch sensitive device

ABSTRACT

The present invention provides a method for detecting a transmitter approximating or touching a touch sensitive device. The transmitter transmits an electrical signal mixed by signals having a plurality of frequencies. The touch sensitive device includes a plurality of first electrodes, a plurality of second electrodes and a plurality of sensing points intersected by those first and second electrodes. The method includes: calculating the signal strength of the electrical signal received by each of the first electrodes and second electrodes; and calculating a relative position between the transmitter and the touch sensitive device according to the calculated signal strengths.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to touch sensitive panels, and moreparticularly, to a touch sensitive panel capable of detecting atransmitter that is transmitting a plurality of frequenciesconcurrently.

2. Description of the Prior Art

Touch sensitive panels or screens are important human-machineinterfaces, especially for consumer electronic products like portablephones, tablet PCs, or Personal Digital Assistances (PDAs). Touchsensitive screens are one of the main input/output (I/O) devices. Ascapacitive touch sensitive screens, especially those of projectedcapacitive types, are highly sensitive to finger touches, it has becomeone of the main design choices for touch sensitive panels/screens on themarket.

Touching the screen with the tip of a finger will inevitably block partof the screen, and the user will not be able to visually confirm a pointthat is being detected by the touch sensitive. In addition, one cannothave as accurate control as using a pen (or stylus) when using theirfinger tip(s) to write. Therefore, in addition to using finger tips fortouch control, users may also wish to use a stylus for input to thescreen.

Generally, the area on a touch sensitive screen touched by the tip of astylus is much smaller than that touched by the fingertips. Forcapacitive touch sensitive screens, it has been a challenge to detectthe capacitive changes caused by a stylus. In particular, in manyprofessional graphics or typesetting application environments, a lot offunctional buttons needs to be added in the design process of thestylus. In view of this demand, the touch sensitive screen not onlyneeds to detect the tiny tip of the stylus, but also needs to determinewhether these buttons are being pressed.

In summary, there is a need on the market for a stylus that supportsmultiple function inputs, thereby allowing a touch sensitive screen todetect a stylus while detecting the statues of the functional buttons.

SUMMARY OF THE INVENTION

In an embodiment, the present invention provides a method for detectinga transmitter approximating or touching a touch sensitive device. Thetransmitter transmits an electrical signal mixed by signals having aplurality of frequencies. The touch sensitive device includes aplurality of first electrodes, a plurality of second electrodes and aplurality of sensing points intersected by those first and secondelectrodes. The method include the steps of: calculating the totalsignal strength of the electrical signal received by each of the firstelectrodes and second electrodes; and calculating a relative positionbetween the transmitter and the touch sensitive device according to thecalculated total signal strengths.

In another embodiment, the present invention provides a touch processingdevice for detecting a transmitter approximating or touching a touchsensitive device. The transmitter transmits an electrical signal mixedby signals having a plurality of frequencies. The touch sensitive deviceincludes a plurality of first electrodes, a plurality of secondelectrodes and a plurality of sensing points intersected by those firstand second electrodes. The touch processing device is used for:calculating the total signal strength of the electrical signal receivedby each of the first electrodes and second electrodes; and calculating arelative position between the transmitter and the touch sensitive deviceaccording to the calculated total signal strengths.

In yet another embodiment, the present invention provides a touchprocessing system for detecting a transmitter approximating or touchinga touch sensitive device. The transmitter transmitting an electricalsignal mixed by signals having a plurality of frequencies. The touchprocessing system includes: the touch sensitive device including aplurality of first electrodes, a plurality of second electrodes and aplurality of sensing points intersected by those first and secondelectrodes; and a touch processing device for calculating the totalsignal strength of the electrical signal received by each of the firstelectrodes and second electrodes, and calculating a relative positionbetween the transmitter and the touch sensitive device according to thecalculated total signal strengths.

In summary, one of the main principles of the present invention lies indetecting the signal strengths corresponding to a plurality offrequencies in the signal received by the first electrodes and thesecond electrodes in order to calculate a relative position of thetransmitter with respect to the touch sensitive device, and to obtainthe statues of various sensors on the transmitter based on the derivedtransmitter status.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram illustrating a transmitter in accordancewith an embodiment of the present invention.

FIG. 2 is a flowchart illustrating a transmitting method in accordancewith an embodiment of the present invention.

FIG. 3 is a schematic diagram depicting a touch sensitive system inaccordance with an embodiment of the present invention.

FIG. 4 is a block diagram depicting a portion of the touch processingdevice in accordance with an embodiment of the present invention.

FIG. 5 is a block diagram depicting a portion of an analog demodulatorin accordance with an embodiment of the present invention.

FIG. 6 is a block diagram depicting a portion of a digital demodulatorin accordance with an embodiment of the present invention.

FIG. 7 is a block diagram depicting a portion of a digital demodulatorin accordance with an embodiment of the present invention.

FIG. 8 is a schematic diagram depicting the result of demodulationaccording to the digital demodulator of FIG. 7.

FIG. 9A is a flowchart illustrating a method for sensing a transmitterin accordance with an embodiment of the present invention.

FIG. 9B is a flowchart illustrating a method for sensing a transmitterin accordance with an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is described in details with reference to someembodiments below. However, in addition to the disclosed embodiments,the scope of the present invention is not limited by these embodiments,rather by the scope of the claims. Moreover, in order for one withordinary skills in the art to have a better understanding and clarity ofthe descriptions, some components in the drawings may not necessary bedrawn to scale, in which some may be exaggerated relative to others, andirrelevant parts are omitted.

In an embodiment, the transmitter mentioned in the present invention maybe a stylus. In some embodiments, the transmitter may be other types ofobjects that can be placed on a touch sensitive panel or screen. Forexample, when the touch sensitive screen displays a chessboard, thetransmitter may be the chess. Once the game program detects the locationof the chess on the touch sensitive screen, it will know the location ofthe chess.

Regardless of how much contact area there is between the transmitter andthe touch sensitive panel and how many touch points there are, thetransmitter at least includes a transmitting anchor point. The touchsensitive panel or screen may detect the location of the transmittinganchor point as the representative location of an object represented bythe transmitter on the touch sensitive panel or screen. In anembodiment, the transmitter does not need to come into contact with thetouch sensitive panel, only the transmitting anchor point needs to be inproximity to the touch sensitive panel for the touch sensitive panel todetect the transmitting anchor point.

In an embodiment, the transmitter may include a plurality oftransmitting anchor points. When the touch sensitive panel detects aplurality of transmitting anchor points, it is able to detect the facingdirection of the transmitter. In another embodiment, the transmitter mayinclude m transmitting anchor points, and when the touch sensitive paneldetects n of the transmitting anchor points, it is able to detect thestance of the transmitter on the touch sensitive panel. For example, thetransmitter is a triangular body with four transmitting anchor points;each transmitting anchor point is positioned at one vertex of thetriangular body, by detecting three transmitting anchor points on thetouch sensitive panel, the touch sensitive panel will be able to knowwhich face of the triangular body is in contact with it. The transmittermay also be a square body with eight transmitting anchor points, whereeach transmitting anchor point is positioned at a vertex of the squarebody. This type of transmitter can be used as a dice.

Referring to FIG. 1, a schematic diagram illustrating a transmitter 100in accordance with an embodiment of the present invention is shown. Thetransmitter 100 includes a power supply module 110, a processing module120, a sensor module 130, a frequency synthesizer module 140, a signalamplifying module 150 and a transmitting module 160. As mentioned above,the transmitter 100 may assume the shape of a stylus. In an embodiment,the above modules may be arranged inside the stylus according to theorder shown in FIG. 1, the bottom of the stylus is to be in contact withor proximity to a touch sensitive panel. The transmitter 100 may includea master switch for turning on/off the power of the transmitter 100.

The power supply module 110 may include circuits associated with powersupply and control, such as a battery pack, a DC-to-DC voltageconverter, a power management unit and the like. The battery pack can berechargeable batteries or disposable batteries. When the battery packincludes rechargeable batteries, the power supply module 110 may furtherinclude a charger circuit for inputting an external power into therechargeable batteries. In an embodiment, the charger circuit can beincluded in the power management unit for protecting the rechargeablebatteries from over discharging and over charging.

The above processing module 120 is used for controlling the transmitter100, and may include a microprocessor. The above sensor module 130 mayinclude at least one sensor. The sensor may, for example, include apressure sensor at the tip of the stylus, a button, an accelerometer, aninductance meter, a knob, or the like. The status of the sensor may bein binary form. For example, the button may be in either a pressed-downstatus or a released status. The statuses of an accelerometer mayinclude stationary and in motion. The statuses of the sensor may includen-ary discrete values. For example, the pressure experienced by thepressure sensor may be divided into four levels, ten levels, or sixteenlevels. The statuses of the knob may also be in four levels, ten levels,or sixteen levels. The status of the sensor can also be an analoginterval. The above processing module 120 is able to detect the statusof the sensor in the sensor module 130, and generate a transmitterstatus accordingly.

The above frequency synthesizer module 140 includes a plurality offrequency generators and a frequency synthesizer or mixer. In oneembodiment, the above plurality of frequency generators may include aplurality of quartz oscillators. In another embodiment, the abovefrequency generators can use a single frequency source, and generate aplurality of frequencies through the use of dividers, frequencymultipliers, phase lock circuits and other appropriate circuitries.These frequencies are not mutually resonant frequency waves, anddifferent from and not mutually resonant with the frequency emitted bythe touch sensitive panel for detecting the transmitter 100. This avoidsinterference between the various frequencies.

In some embodiments, the ranges of the plurality of frequencies fallwithin the detectable frequency range of the touch sensitive panel. Forexample, a frequency range that generally can be detected by a touchsensitive panel is approximately between 90 kHz and 250 kHz, so thefrequencies generated by the plurality of frequency generators may fallwithin this range.

In an embodiment, the above processing module 120 may decide whichfrequencies in the plurality of frequencies are to be synthesized by thefrequency synthesizer module 140. In other words, a specific frequencycan be controlled not to be added to the mixer. Of course, the signalstrength of an individual frequency may also be controlled. In anotherembodiment, the above processing module 120 may decide the ratios of thesignal strengths of the various frequencies for the frequencysynthesizer module 140. For example, the ratio of the signal strength ofa first frequency to that of a second frequency may be 3:7. As anotherexample, the ratio of the signal strengths between a first, a second anda third frequency may be 24:47:29. One with ordinary skills in the artcan appreciate that although the frequency synthesizer module 140 can beused for generating and mixing multiple frequencies, the processingmodule 120 may also instruct the frequency synthesizer module 140 togenerate a single frequency without mixing with any other frequenciesbased on the statuses of the sensors in the sensor module 130.

In an embodiment, the signal strength of a particular frequency maycorrespond to a pressure sensor at the tip of the stylus or a knob withmultiple levels in the sensor module 130. For example, in a graphicssoftware, the pressure sensor at the tip of a stylus may indicate theshades of the color, and the degree of rotation of the knob may indicatethe diameter of the brush. Thus, the signal strength of a firstfrequency can be used to indicate the pressure on the pressure sensor,and the signal strength of a second frequency can be used to indicatethe degree of rotation of the knob.

In another embodiment, the proportion of the signal strength of onefrequency among the signal strength of the mixed frequencies can be usedto correspond to one of the n-ary statuses of a sensor. For example,when the ratio of the signal strengths of a first frequency to a secondfrequency is 3:7, it indicates the status of the sensor is in the thirdlevel among ten levels. If the ratio of the strengths is changed to 6:4,this indicates the status of the sensor is in the sixth level among tenlevels. In other words, if there are three frequencies, then the ratioof the signal strengths of a first frequency to a second frequency, theratio of the signal strengths of the second frequency to a thirdfrequency, and the ratio of the signal strengths of the third frequencyto the first frequency can be used to indicate three statuses of then-ary sensor, respectively.

The above signal amplifying module 150 is used for amplifying the signalmixed by the frequency synthesizer module 140. In an embodiment, theabove signal amplification corresponds to the pressure sensor in thesensor module 130 at the tip of the stylus. If the circuit of thepressure sensor corresponds to a variable gain amplifier (VGA) of thesignal amplifying module 150, the circuit of the pressure sensor maydirectly control the gain of the VGA without going through theprocessing module 120. Therefore, the mixed signal outputted by thefrequency synthesizer module 140 can be amplified by the VGA and sent tothe transmitting module 160.

As mentioned before, the signal strength of a particular frequency inthe mixed signal can be used to indicate a status of an n-ary sensor.The ratio of the signal strengths of two frequencies in the mixed canalso be used to indicate a status of another n-ary sensor. Meanwhile,the signal amplifying module 150 can be use to amplify the mixed signalto indicate the status of yet another n-ary sensor. For example, thetransmitter 100 includes two n-ary sensors: one is a pressure sensorprovided at the tip of the stylus, and the second one is a knob providedon the body of the stylus, they are used to indicate the color shade andthe diameter of the stylus, respectively. In an embodiment, the strengthof the mixed signal can be used to indicate the degree of pressureexperienced by the pressure sensor. The status of the knob can beindicated by the ratio of the signal strengths of two frequencies in themixed signal.

In an embodiment of the present invention, the transmitting module 160includes a pressure sensor provided at the tip of the stylus. Thetransmitting module 160 can be an array of antennas or a conductor or anelectrode with the appropriate impedance value, which can also be calledan excitation electrode. The conductor or electrode at the tip of thestylus is connected to the pressure sensor. When the transmitting module160 emits a signal and touches the touch sensitive panel/screen, thesignal will flow into the sensing electrodes of the touch sensitivepanel/screen. When the transmitting module 160 is near but not incontact with the touch sensitive panel/screen, the sensing electrodes ofthe touch sensitive panel/screen may still experience the signalvariations on the transmitting module 160, thereby allowing the touchsensitive/panel to detect the approaching of the transmitter 100.

When the frequency synthesizer module 140 synthesizes n frequencies, thefrequencies of the signal can be used to modulate 2^(n) statues. Forexample, when n equals to three, the frequencies of the signal can beused to modulate eight statues. Referring to Table 1, the transmitterstatuses and their corresponding statuses of the sensors are shown.

TABLE 1 Pressure Sensor First Button Second Button First TransmitterContact Pressure Released Released Status Second Transmitter ContactPressure Pressed Released Status Third Transmitter Contact PressurePressed Pressed Status Fourth Transmitter Contact Pressure ReleasedPressed Status Fifth Transmitter No Contact Pressure Released ReleasedStatus Sixth Transmitter No Contact Pressure Pressed Released StatusSeventh Transmitter No Contact Pressure Pressed Pressed Status EighthTransmitter No Contact Pressure Released Pressed Status

In the embodiment shown by Table 1, the sensor module 130 includes threesensors: a pressure sensor at the tip of the stylus, a first button anda second button. The status of these three sensors are all in binaryforms, so there are eight different combinations of transmitter statusesin total, as shown in Table 1. One with ordinary skills in the art canappreciate that the correspondence between the transmitter statuses andthe sensors' statuses can be arbitrarily changed. For example, the firsttransmitter status can swap with another transmitter status, forexample, the seventh transmitter status.

Referring to Table 2, the transmitter statuses and their correspondingfrequency mixings are shown. As described before, the frequencysynthesizer module 140 may synthesize three different frequencies, soeach transmitter status may correspond to a different combination of thefrequencies as shown in Table 2. One with ordinary skills in the art canappreciate that the correspondence between the transmitter statuses andthe combinations of frequencies can be arbitrarily changed. For example,the first transmitter status can swap with another transmitter status,for example, the eighth transmitter status.

TABLE 2 First Second Third Frequency Frequency Frequency FirstTransmitter Mixed Mixed Mixed Status Second Transmitter Mixed Mixed NotMixed Status Third Transmitter Mixed Not Mixed Not Mixed Status FourthTransmitter Mixed Not Mixed Mixed Status Fifth Transmitter Not MixedMixed Mixed Status Sixth Transmitter Not Mixed Mixed Not Mixed StatusSeventh Transmitter Not Mixed Not Mixed Not Mixed Status EighthTransmitter Not Mixed Not Mixed Mixed Status

In an embodiment, when the pressure sensor at the tip of the stylus isnot under any pressure, the transmitter 100 still mixes the frequenciesand sends out a signal. In another embodiment, when the pressure sensorat the tip of the stylus is not under any pressure, the transmitter 100does not mix the frequencies and transmit any signal. With respect toTable 2, this status is the seventh transmitter status. In thisembodiment, Table 1 can be altered into Table 3.

TABLE 3 Pressure Sensor First Button Second Button First TransmitterContact Pressure Released Released Status Second Transmitter ContactPressure Pressed Released Status Third Transmitter Contact PressurePressed Pressed Status Fourth Transmitter Contact Pressure ReleasedPressed Status Seventh Transmitter No Contact Pressure Released ReleasedStatus Seventh Transmitter No Contact Pressure Pressed Released StatusSeventh Transmitter No Contact Pressure Pressed Pressed Status SeventhTransmitter No Contact Pressure Released Pressed Status

In the embodiments shown in Table 1 to Table 3, the transmitter 100 usesthe synthesizing of the frequencies as the only factor of signalmodulation. In the following embodiments, in addition to frequencysynthesizing, signal strength and/or ratio of signal strengths ofdifferent frequencies are included as the factors of signal modulation.

Referring to Table. 4, transmitter frequency statuses and theircorresponding sensors' statuses in accordance with an embodiment of thepresent invention are shown. Compared to the embodiment shown in Table1, the statues sensed by the pressure sensor are not limited to twostatuses (i.e. contact pressure/no contact pressure), but more than twostatuses. Thus, the left column of Table 4 is not called transmitterstatus anymore, but rather transmitter frequency status. The modulationfactors of the transmitter status of this embodiment include, inaddition to the frequency status, the signal strength as well.

TABLE 4 Pressure Sensor First Button Second Button First TransmitterContact Pressure Released Released Frequency Status Level > 0 SecondTransmitter Contact Pressure Pressed Released Frequency Status Level > 0Third Transmitter Contact Pressure Pressed Pressed Frequency StatusLevel > 0 Fourth Transmitter Contact Pressure Released Pressed FrequencyStatus Level > 0 Fifth Transmitter Contact Pressure Released ReleasedFrequency Status Level = 0 Sixth Transmitter Contact Pressure PressedReleased Frequency Status Level = 0 Seventh Transmitter Contact PressurePressed Pressed Frequency Status Level = 0 Eighth Transmitter ContactPressure Released Pressed Frequency Status Level = 0

Referring to Table 5, transmitter statuses and their correspondingfrequency mixings and signal strengths in accordance with an embodimentof the present invention are shown. The signal strength modulation canbe the signal strength value of the mixed signal to indicate, forexample, the contact pressure level of the pressure sensor.

TABLE 5 First Second Third Frequency Frequency Frequency FirstTransmitter Mixed Mixed Mixed Frequency Status + Signal StrengthModulation Second Transmitter Mixed Mixed Not Mixed Frequency Status +Signal Strength Modulation Third Transmitter Mixed Not Mixed Not MixedFrequency Status + Signal Strength Modulation Fourth Transmitter MixedNot Mixed Mixed Frequency Status + Signal Strength Modulation FifthTransmitter Not Mixed Mixed Mixed Frequency Status + Signal StrengthModulation Sixth Transmitter Not Mixed Mixed Not Mixed FrequencyStatus + Signal Strength Modulation Seventh Transmitter Not Mixed NotMixed Not Mixed Frequency Status + Signal Strength Modulation EighthTransmitter Not Mixed Not Mixed Mixed Frequency Status + Signal StrengthModulation

In the embodiment of Table 5, the contact pressure levels of thepressure sensor corresponding to the fifth to the eighth transmitterfrequency statues are all zero, so the results of signal strengthmodulation can also be zero. In other words, no signal is transmitted.In another embodiment, such a signal strength modulation can be aconstant. This constant signal strength can be different from the signalstrengths corresponding to other contact pressure levels of the pressuresensor.

Referring to FIG. 2, a flowchart illustrating a transmitting method inaccordance with an embodiment of the present invention is shown. Thetransmitting method is applicable to the transmitter 100 shown in FIG.1, but not limited thereto. The transmitting method includes two steps.In step 210, a transmitter status is generated based on a status insidea sensor module included in the transmitter. In step 220, an electricalsignal is transmitted to a touch sensitive device according to thetransmitter status, so that after analyzing the electrical signal, thetouch sensitive device is able to find out the transmitter status and arelative position of the transmitter with respect to the touch sensitivedevice. The electrical signal is mixed from a plurality of signalshaving different frequencies.

In an embodiment, a sensor inside the sensor module includes one of thefollowing: a button, a knob, a pressure sensor (or a pressure gauge), anaccelerometer or a gyroscope. The pressure sensor can be used to sensethe contact pressure level between the transmitter and the touchsensitive device.

When the sensor module includes a plurality of sensors, the number ofpossible statues of the transmitter status is the sum of the number ofpossible statues of every sensor. Alternatively, in another embodiment,the transmitter status indication is one of arbitrary combinations ofevery sensor's status indication. In an embodiment, the statusindication of a sensor inside the sensor module is the nth power of two,wherein n is an integer greater than or equal to 0.

The modulation factor of the electrical signal includes one or acombination of: frequency and strength. In an embodiment, the totalsignal strength of the electrical signal corresponds to a status of ann-ary sensor in the sensor module. In another embodiment, the ratio ofsignal strengths of a first frequency to a second frequency mixed in theelectrical signal corresponds to a status of an n-ary sensor in thesensor module. In yet another embodiment, the total signal strength ofthe electrical signal corresponds to a status of a first n-ary sensor inthe sensor module, wherein the ratio of the signal strengths of a firstfrequency to a second frequency mixed in the electrical signalcorresponds to a status of a second n-ary sensor in the sensor module.

One main principle of the present invention lies in the use of anelectrical signal mixed from a plurality of frequencies, so that a touchsensitive device may be able to detect the position of a transmittertransmitting the electrical signal and the status of at least one sensoron the transmitter.

Referring now to FIG. 3, a schematic diagram depicting a touch sensitivesystem 300 in accordance with an embodiment of the present invention isshown. The touch sensitive system 300 includes at least one transmitter100, a touch sensitive panel 320, a touch processing device 330 and amainframe 340. In this embodiment, the transmitter 100 is applicable tothe transmitters described in the previous embodiments, especially theembodiments shown in FIGS. 1 and 2. It should also be noted that thetouch sensitive system 300 may include a plurality of transmitters 100.The touch sensitive panel 320 is formed on a substrate. The touchsensitive panel 320 can be a touch sensitive screen, but the presentinvention does not restrict the form of the touch sensitive panel 320.

In an embodiment, a touch sensitive area of the touch sensitive panel320 includes a plurality of first electrodes 321 and a plurality ofsecond electrodes 322. A plurality of sensing points are formed at theintersections of these two electrodes. These first electrodes 321 andsecond electrodes 322 are connected to the touch processing device 330.Under mutual capacitive sensing, the first electrodes 321 can be calledfirst conductive strips or driving electrodes and the second electrodes322 can be called second conductive strips or sensing electrodes. Thetouch processing device 330 is able to know the approach or touch(approach/touch) of any external conductive object on the touchsensitive panel 320 by first providing a driving voltage to the firstelectrodes 321 and then measuring the signal variations of the secondelectrodes 322. One with ordinary skills in the art can appreciate thatthe touch processing device 330 may use mutual- or self-capacitivesensing methods to detect an approaching/touching event or object, andthey will not be further described. In addition to mutual- orself-capacitive sensing methods, the touch processing device 330 mayalso detect the electrical signal emitted by the transmitter 100 inorder to detect the relative position of the transmitter 100 withrespect to the touch sensitive panel 320. The detection principle willbe detailed in the later sections of the specification.

FIG. 3 further includes a mainframe 340, which can be an operatingsystem such as a CPU or a main processor in an embedded system, or othertypes of computers. In an embodiment, the touch sensitive system 300 canbe a table PC. The mainframe 340 can be a CPU for executing theoperating programs of the table PC. For example, the table PC executesan Android operating system, and the mainframe 340 is an ARM processorexecuting the Android operating system. The present invention does notlimit the form of information transmission between the mainframe 340 andthe touch processing device 330 as long as the information transmittedis relevant to the approaching/touching event(s) happened on the touchsensitive panel 320.

Referring to FIG. 4, a block diagram depicting a portion of the touchprocessing device 330 in accordance with an embodiment of the presentinvention is shown. As mentioned earlier, the touch processing device330 may use mutual- or self-capacitive sensing principle to detect anapproaching/touching event, so details related to capacitive sensingwill not be described hereinafter. The embodiment shown in FIG. 4includes a receiver analog front end 410 and a demodulator 420.

The receiver analog front end 410 is connected to the first electrodes321 or the second electrodes 322 described before. In an embodiment,each of the first electrodes 321 and each of the second electrodes 322are connected to a receiver analog front end 410, respectively. Inanother embodiment, a plurality of first electrodes 321 form a set, anda plurality of second electrodes 322 form a set, and each set of firstelectrodes 321 corresponds to a receiver analog front end 410, and eachset of second electrodes 322 corresponds to another receiver analogfront end 410. Each receiver analog front end 410 receives in turn thesignal of the first electrodes 321 or second electrodes 322 in the set.In another embodiment, a set of first electrodes 321 and a set of secondelectrodes 322 correspond to one receiver analog front end 410. Thereceiver analog front end 410 can first be connected in turn to thefirst electrodes 321 in the set of the first electrodes 321, and thenconnected in turn to the second electrodes 322 in the set of the secondelectrodes 322. On the contrary, the receiver analog front end 410 canfirst be connected in turn to the second electrodes 322 in the set ofthe second electrodes 322, and then connected in turn to the firstelectrodes 321 in the set of the first electrodes 321. In an embodiment,the touch processing device 330 may include only one receiver analogfront end 410. One with ordinary skills in the art can appreciate thatthe present invention does not limit how the first electrodes 321 or thesecond electrodes 322 are configured to the receiver analog front end410. In other words, the number of receiver analog front ends 410included in the touch processing device 330 may be smaller than or equalto the sum of the first electrodes 321 and the second electrodes 322.

The receiver analog front end 410 may perform some filtering, amplifyingor other types of analog signal processing. In some embodiments, thereceiver analog front end 410 can receive the difference between twoadjacent first electrodes 321, or the difference between two adjacentsecond electrodes 322. In an embodiment, each receiver analog front end410 can output to a demodulator 420. In another embodiment, every n^(th)receiver analog front end 410 may output to a demodulator 420. In yetanother embodiment, each receiver analog front end 410 may output to Ndemodulators 420, wherein N is a positive integer greater than or equalto one. In some embodiments, the touch processing device 330 may includeonly one demodulator 420. One with ordinary skills in the art canappreciate that the present invention does not limit how the receiveranalog front end(s) 410 is/are configured to the demodulator(s) 420.

The demodulator 420 is used to demodulate the electrical signaltransmitted by the transmitter 100 in order to obtain information oneach frequency and information on the signal strengths in the receivedsignals of the corresponding first electrodes 321 or second electrodes322. For example, the transmitter 100 may transmit a signal having threefrequencies. The demodulator 420 may obtain the signal strengths forthese three frequencies, the ratio(s) of signal strengths of each two orarbitrary two frequencies, and the overall signal strength. In thepresent invention, the demodulator 420 can be implemented in a digitalor analog way; it is described in the following three embodiments.

Referring to FIG. 5, a block diagram depicting a portion of an analogdemodulator 420 in accordance with an embodiment of the presentinvention is shown. A single analog demodulator shown in FIG. 5 can beused to demodulate every frequency, or a plurality of analogdemodulators shown in FIG. 5 can be used to demodulate a plurality offrequencies. For example, when the transmitter 100 transmits Nfrequencies, N of the analog demodulator shown in FIG. 5 are used todemodulate each of the frequencies. A signal generator 510 is used togenerate signals of corresponding frequencies.

An analog signal received from the receiver analog front end 410 can bepassed through an optional amplifier (not shown) and then to two mixers520I and 520Q. The mixer 520I receives a cosine signal outputted by thesignal generator 510, while the mixer 520Q receives a sine signaloutputted by the signal generator 510. The mixer signals outputted bythe mixers 520I and 520Q are then sent to integrators 530I and 530Q,respectively. Then, the integrated signals are sent to squarers 540I and540Q by the integrators 530I and 530Q, respectively. Finally, theoutputs of the squarers 540I and 540Q are summed and thenroot-mean-squared by a “Root Mean Square (RMS) of Sum” element. As such,the signal strengths corresponding to the signal frequencies generatedby the signal generator 510 can be obtained. After the signal strengthsof all frequencies are obtained, the ratio(s) of the signal strengths ofeach two or arbitrary two frequencies and the overall signal strengthcan then be generated.

Referring to FIG. 6, a block diagram depicting a portion of a digitaldemodulator 420 in accordance with an embodiment of the presentinvention is shown. Compared to the embodiment shown in FIG. 5, theembodiment shown in FIG. 6 is carried out in a digital manner.Similarly, a single digital demodulator shown in FIG. 6 can be used todemodulate every frequency, or a plurality of the digital demodulatorsshown in FIG. 6 can be used to demodulate a plurality of frequencies.For example, when the transmitter 100 transmits N frequencies, N of thedigital demodulator shown in FIG. 6 are used demodulate each of thefrequencies. A signal generator 610 is used to generate digital signalsof corresponding frequencies.

An analog signal received from the receiver analog front end 410 can bepassed through an optional amplifier 600 and then to ananalog-to-digital converter (ADC) 605. The sampling frequency of the ADC605 will correspond to the frequency of the signal transmitted by thesignal generator 610. In other words, when the ADC 605 is performing onesampling, the signal generator 610 will send out signals to two mixers620I and 620Q once. The mixer 620I receives a cosine signal outputted bythe signal generator 610, while the mixer 620Q receives a sine signaloutputted by the signal generator 610. The mixer signals outputted bythe mixers 620I and 620Q are then outputted to addition integrators 630Iand 630Q, respectively. Then, the addition-integrated signals are sentto squarers 640I and 640Q by the addition integrators 630I and 630Q,respectively. Finally, the outputs of the squarers 640I and 640Q aresummed and root-mean-squared by a “Root Mean Square (RMS) of Sum”element. As such, the signal strengths corresponding to the signalfrequencies generated by the signal generator 610 can be obtained. Afterthe signal strengths of all frequencies are obtained, the ratios of thesignal strengths of each two frequencies and the overall signal strengthcan then be generated.

Referring to FIG. 7, a block diagram depicting a portion of a digitaldemodulator 420 in accordance with an embodiment of the presentinvention is shown. The embodiment shown in FIG. 7 is carried out in adigital manner, and a single digital demodulator shown in FIG. 7 can beused to demodulate every frequency. An analog signal received from thereceiver analog front end 410 can be passed through an optionalamplifier 700 and then to an analog-to-digital converter (ADC) 705.Then, the outputted digital signal is sent to a Fourier transformer 720to demodulate the signal strength of each frequency on the frequencydomain. The above Fourier transformer can be a digitalized Fast Fouriertransformer.

Referring to FIG. 8, a schematic diagram depicting the result ofdemodulation according to the digital demodulator 420 of FIG. 7 isshown. The result shown in FIG. 8 is merely an illustration, in additionto being represented by a diagram; other kinds of data structure can beused to store the result of demodulation. The horizontal axis shown inFIG. 8 indicates the signal frequency, and the vertical axis thereofindicates the signal strength. The calculated result from the Fouriertransformer 720 gives the signal strengths corresponding to Nfrequencies possibly transmitted by the transmitter 100. In anembodiment, a threshold can be set for the signal strength. Only asignal with strength greater than the threshold would be regarded as asignal having a corresponding frequency. When the signal strength ofeach frequency is obtained, the ratios of each two frequencies and theoverall signal strength can then be calculated.

Although the embodiments of the three demodulators 420 provided in FIGS.5 to 7 can be implemented in the touch processing device 330 shown inFIG. 3, but the present invention does not restrict that the touchprocessing device 330 must implement all the steps of the demodulator420. In some embodiments, some steps of the demodulator 420 can beperformed by the mainframe 340. It should be noted that although theembodiments of the demodulators 420 can be implemented by specifichardware, but one with ordinary skills in the art can appreciate thateach elements of the demodulators 420 can be implemented throughsoftware or firmware. For example, the mixers can be implemented bymultiplication, and the addition integrators can be implemented byaddition. Multiplication and addition are among the most commonoperation instructions in ordinary processors.

Referring to FIG. 9A, a flowchart illustrating a method for sensing atransmitter in accordance with an embodiment of the present invention isshown. In step S910, the overall signal strength of the electricalsignal received by every one of the first and second electrodes iscalculated. Step 910 can be implemented using the embodiments shown inFIGS. 3 to 7. Then, in step 920, based on the calculated overall signalstrength, a relative position of the transmitter with respect to a touchsensitive device is calculated. In an embodiment, the position of thetransmitter is thought to be corresponding to the first and secondelectrodes having the largest overall signal strengths. In anotherembodiment, the position of the transmitter is thought to becorresponding to the centroid of adjacent first and second electrodeshaving the largest overall signal strengths, the magnitude of the massesof these electrodes correspond to the strength of the signals. Finally,in an optional step 930, based on information of the electrical signaltransmitted by the transmitter, a transmitter status is calculated. Onewith ordinary skills in the art can appreciate that the implementationof step 930 can be deduced from the tables previously described.

Referring to FIG. 9B, a flowchart illustrating a method for sensing atransmitter in accordance with an embodiment of the present invention isshown. In step 905, the overall signal strength of the electrical signalreceived by every first or second electrode is calculated. Once theelectrical signal received by a first or second electrode isdemodulated, the frequencies of the signal transmitted by thetransmitter can be known. For example, if the transmitter transmits afirst frequency and a second frequency, but not a third frequency, thenin the calculation of overall signal strengths of another electrodecarried out in step 915, the calculation of the third frequency can beomitted. If the digital demodulator shown in FIG. 7 is employed, thenthe method shown in FIG. 9B is not required. However, if the demodulatordescribed with respect to FIG. 5 or FIG. 6 is employed, and that thenumber of demodulators is not be enough to scan all frequencies in onego, then the method of FIG. 9B can save some time and calculationresources. Moreover, if after the calculations of the first electrodesor the second electrodes, no electrical signal transmitted by thetransmitter is found, step 915 can be bypassed. On the contrary, if theelectrical signal transmitted by the transmitter is found, then step 915can calculate the overall signal strength of the electrical signalreceived by another electrode based on the signal strength of eachfrequency of the received electrical signal. The descriptions of theembodiment of FIG. 9A apply to the remaining steps 920 and 930.

It should be noted that in the processes of FIGS. 9A and 9B, if nocause-and-effect relationships or order between the steps are mentioned,then the present invention does not limit the order in which these stepsare carried out. In addition, in steps 905, 910 and 915, the overallsignal strength of the electrical signal of every first and/or secondelectrode(s) is mentioned. In an embodiment, if the touch sensitivesystem 300 includes only a single transmitter 100, the processes ofFIGS. 9A and 9B will be modified to: if the overall strength of theelectrical signal received by at least one first electrode and secondelectrode is calculated to be greater than a threshold, then executesteps 920 and 930.

In an embodiment, the present invention provides a method for detectinga transmitter approximating or touching a touch sensitive device. Thetransmitter transmits an electrical signal mixed by signals having aplurality of frequencies. The touch sensitive device includes aplurality of first electrodes, a plurality of second electrodes and aplurality of sensing points intersected by those first and secondelectrodes. The method includes the following steps of: calculating thetotal signal strength of the electrical signal received by each of thefirst electrodes and second electrodes; and calculating a relativeposition between the transmitter and the touch sensitive deviceaccording to the calculated total signal strengths.

The above step of calculating the total signal strength of theelectrical signal received by each of the first electrodes and secondelectrodes further includes: calculating the strength of a signalcorresponding to each of the plurality of frequencies in the receivedelectrical signal; and summing all of the calculated strengths ofsignals corresponding to the plurality of frequencies. In an embodiment,the above step of calculating the strength of a signal corresponding toa particular frequency of the plurality of frequencies further includes:mixing an in-phase signal with the received signal to generate anin-phase analog signal, mixing an orthogonal signal with the receivedsignal to generate an orthogonal analog signal, wherein the frequency ofthe in-phase signal and the orthogonal signal is the particularfrequency; performing integration on the in-phase analog signal togenerate an in-phase integration signal, performing integration on theorthogonal analog signal to generate an orthogonal integration signal;and calculating the root mean square of the sum of the square of thein-phase integration signal and the square of the orthogonal integrationsignal to obtain the signal strength corresponding to the particularfrequency. In another embodiment, the above step of calculating thestrength of a signal corresponding to a particular frequency of theplurality of frequencies further includes: performing analog-to-digitalconversion on the received signal to produce a digital received signal;mixing an in-phase signal with the digital received signal to generatean in-phase digital signal; mixing an orthogonal signal with thereceived signal to generate an orthogonal digital signal, wherein thefrequency of the in-phase signal and the orthogonal signal is theparticular frequency; performing addition integration on the in-phasedigital signal to generate an in-phase integration signal; performingaddition integration on the orthogonal digital signal to generate anorthogonal integration signal; and calculating the root mean square ofthe sum of the square of the in-phase integration signal and the squareof the orthogonal integration signal to obtain the strength of signalcorresponding to the particular frequency. The frequency of theanalog-to-digital conversion corresponds to the particular frequency. Instill another embodiment, the above step of calculating the strength ofa signal corresponding to a particular frequency of the plurality offrequencies further includes: performing analog-to-digital conversion onthe received signal to produce a digital received signal; and performingFourier transform on the digital received signal to generate thestrength of the signal corresponding to each frequency of the pluralityof frequencies.

The above step of calculating the total signal strength of theelectrical signal received by each of the first electrodes and secondelectrodes further includes: calculating the total signal strength ofthe electrical signal received by each first electrode; calculating thestrength of a signal corresponding to each of the plurality offrequencies based on the electrical signal received by at least onefirst electrode to obtain a set of frequencies mixed by the transmitter;and calculating the total signal strength corresponding to all of thefrequencies in the set of frequencies in the electrical signal receivedby the second electrode, wherein a signal strength corresponding to eachfrequency in the set of frequencies is greater than a threshold.

In an embodiment, while calculating the total signal strength of theelectrical signal received by a particular first electrode, the totalsignal strength of the electrical signal received by a particular secondelectrode is calculated.

The transmitter transmits the electrical signal according to atransmitter status. The method further includes calculating thetransmitter status based on the information of the electrical signal.The above calculating the transmitter status is based on one or anyarbitrary combination of the following information of the electricalsignal: the signal strength of a particular frequency in the pluralityof frequencies mixed by the electrical signal; the total signal strengthof the electrical signal; and the ratio of signal strengths of a firstfrequency to a second frequency in the plurality of frequencies mixed bythe electrical signal. In an embodiment, the total signal strength ofthe electrical signal corresponds to the status of a sensor with n-arypossible statuses in the transmitter. In another embodiment, the ratioof the signal strengths of the first frequency to the second frequencymixed by the electrical signal corresponds to the status of a sensorwith n-ary possible statuses in the transmitter. In still anotherembodiment, the total signal strength of the electrical signalcorresponds to the status of a first sensor with n-ary possible statusesin the transmitter, wherein the ratio of signal strengths of the firstfrequency to the second frequency in the plurality of frequencies mixedby the electrical signal corresponds to the status of a second sensorwith n-ary possible statuses in the transmitter.

In an embodiment, when the transmitter includes a plurality of sensors,the number of possible statuses of the transmitter status is the sum ofthe number of possible statuses of every one of the plurality ofsensors. In another embodiment, the transmitter status indication is oneof arbitrary combinations of every sensor's status indication.

The present invention provides a touch processing device for detecting atransmitter approximating or touching a touch sensitive device. Thetransmitter transmits an electrical signal mixed by signals having aplurality of frequencies. The touch sensitive device includes aplurality of first electrodes, a plurality of second electrodes and aplurality of sensing points intersected by those first and secondelectrodes. The touch processing device is used for: calculating thetotal signal strength of the electrical signal received by each of thefirst electrodes and second electrodes; and calculating a relativeposition between the transmitter and the touch sensitive deviceaccording to the calculated total signal strengths.

The above step of calculating the total signal strength of theelectrical signal received by each of the first electrodes and secondelectrodes further includes: calculating the strength of a signalcorresponding to each of the plurality of frequencies in the receivedelectrical signal; and summing all of the calculated strengths ofsignals corresponding to the plurality of frequencies. In an embodiment,the touch processing device further includes a demodulator forcalculating the strength of a signal corresponding to a particularfrequency of the plurality of frequencies. The demodulator furtherincludes: a signal generator for generating an in-phase signal and anorthogonal signal, wherein the frequency of the in-phase signal and theorthogonal signal is the particular frequency; at least a mixer formixing the in-phase signal with the received signal to generate anin-phase analog signal, and mixing the orthogonal signal with thereceived signal to generate an orthogonal analog signal; at least anintegrator for performing integration on the in-phase analog signal togenerate an in-phase integration signal, and performing integration onthe orthogonal analog signal to generate an orthogonal integrationsignal; at least a squarer for calculating the square of the in-phaseintegration signal and the square of the orthogonal integration signal;and at least a “Root Mean Square (RMS) of Sum” element for calculatingthe root mean square of the sum of the square of the in-phaseintegration signal and the square of the orthogonal integration signalto obtain the signal strength corresponding to the particular frequency.In another embodiment, the touch processing device further includes ademodulator for calculating the strength of a signal corresponding to aparticular frequency of the plurality of frequencies. The demodulatorfurther includes: an analog-to-digital converter (ADC) for performinganalog-to-digital conversion on the received signal to produce a digitalreceived signal; a signal generator for generating an in-phase signaland an orthogonal signal, wherein the frequency of the in-phase signaland the orthogonal signal is the particular frequency; at least a mixerfor mixing the in-phase signal with the digital received signal togenerate an in-phase digital signal, and mixing the orthogonal signalwith the digital received signal to generate an orthogonal digitalsignal; at least an addition integrator for performing additionintegration on the in-phase digital signal to generate an in-phaseintegration signal, and performing integration on the orthogonal digitalsignal to generate an orthogonal integration signal; at least a squarerfor calculating the square of the in-phase integration signal and thesquare of the orthogonal integration signal; and at least a “Root MeanSquare (RMS) of Sum” element for calculating the root mean square of thesum of the square of the in-phase integration signal and the square ofthe orthogonal integration signal to obtain the signal strengthcorresponding to the particular frequency. In still another embodiment,the touch processing device further includes a demodulator forcalculating the strength of a signal corresponding to each of theplurality of frequencies. The demodulator further includes: ananalog-to-digital converter (ADC) for performing analog-to-digitalconversion on the received signal to produce a digital received signal;and a Fourier Transformer for performing Fourier Transform on thedigital received signal to generate the strength of the signalcorresponding to each of the plurality of frequencies.

In an embodiment, the step of calculating the total signal strength ofthe electrical signal received by each of the first electrodes andsecond electrodes further includes: calculating the total signalstrength of the electrical signal received by each first electrode;calculating the strength of a signal corresponding to each of theplurality of frequencies based on the electrical signal received by atleast one first electrode to obtain a set of frequencies mixed by thetransmitter; and calculating the total signal strength corresponding toall of the frequencies in the set of frequencies in the electricalsignal received by the second electrode, wherein a signal strengthcorresponding to each frequency in the set of frequencies is greaterthan a threshold.

While calculating the total signal strength of the electrical signalreceived by a particular first electrode, the total signal strength ofthe electrical signal received by a particular second electrode iscalculated.

The transmitter transmits the electrical signal according to atransmitter status. The touch processing device further includescalculating the transmitter status based on the information of theelectrical signal. The above calculating the transmitter status is basedon one or any arbitrary combination of the following information of theelectrical signal: the signal strength of a particular frequency in theplurality of frequencies mixed by the electrical signal; the totalsignal strength of the electrical signal; and the ratio of signalstrengths of a first frequency to a second frequency in the plurality offrequencies mixed by the electrical signal.

In an embodiment, the total signal strength of the electrical signalcorresponds to the status of a sensor with n-ary possible statuses inthe transmitter. In another embodiment, the ratio of the signalstrengths of the first frequency to the second frequency mixed by theelectrical signal corresponds to the status of a sensor with n-arypossible statuses in the transmitter. In still another embodiment, thetotal signal strength of the electrical signal corresponds to the statusof a first sensor with n-ary possible statuses in the transmitter,wherein the ratio of signal strengths of the first frequency to thesecond frequency in the plurality of frequencies mixed by the electricalsignal corresponds to the status of a second sensor with n-ary possiblestatuses in the transmitter.

In an embodiment, when the transmitter includes a plurality of sensors,the number of possible statuses of the transmitter status is the sum ofthe number of possible statuses of every one of the plurality ofsensors. In another embodiment, the transmitter status indication is oneof arbitrary combinations of every sensor's status indication.

The present invention provides a touch processing system for detecting atransmitter approximating or touching a touch sensitive device. Thetransmitter transmits an electrical signal mixed by signals having aplurality of frequencies. The touch processing system includes: thetouch sensitive device including a plurality of first electrodes, aplurality of second electrodes and a plurality of sensing pointsintersected by those first and second electrodes; and a touch processingdevice for calculating the total signal strength of the electricalsignal received by each of the first electrodes and second electrodes;and calculating a relative position between the transmitter and thetouch sensitive device according to the calculated total signalstrengths.

In summary, one of the main principles of the present invention lies indetecting the signal strengths corresponding to a plurality offrequencies in the signal received by the first electrodes and thesecond electrodes in order to calculate a relative position of thetransmitter with respect to the touch sensitive device, and to obtainthe statues of various sensors on the transmitter based on the derivedtransmitter status. Moreover, the present invention may also make use ofthe touch sensitive electrodes of capacitive touch sensitive panels,thus allowing the same capacitive touch sensitive panel to perform bothcapacitive sensing and the detection of the transmitter. In other words,the same capacitive touch sensitive panel can be used for the detectionsof fingers, palms, as well as transmitter-type styli.

What is claimed is:
 1. A method for detecting a transmitter approximating or touching a touch sensitive device, the transmitter transmitting an electrical signal mixed by signals having a plurality of frequencies, the touch sensitive device including a plurality of first electrodes, a plurality of second electrodes and a plurality of sensing points intersected by those first and second electrodes, the method comprising the steps of: calculating the strength of a signal corresponding to each of the plurality of frequencies in the electrical signal received by each of the first electrodes and second electrodes; summing all of the calculated strengths of signals corresponding to the plurality of frequencies; and calculating a relative position between the transmitter and the touch sensitive device according to the calculated total signal strengths.
 2. The method of claim 1, wherein the step of calculating the strength of a signal corresponding to a particular frequency of the plurality of frequencies further includes: mixing an in-phase signal with the received signal to generate an in-phase analog signal; mixing an orthogonal signal with the received signal to generate an orthogonal analog signal, wherein the frequency of the in-phase signal and the orthogonal signal is the particular frequency; performing integration on the in-phase analog signal to generate an in-phase integration signal; performing integration on the orthogonal analog signal to generate an orthogonal integration signal; and calculating the root mean square of the sum of the square of the in-phase integration signal and the square of the orthogonal integration signal to obtain the signal strength corresponding to the particular frequency.
 3. The method of claim 1, wherein the step of calculating the strength of a signal corresponding to a particular frequency of the plurality of frequencies further includes: performing analog-to-digital conversion on the received signal to produce a digital received signal; mixing an in-phase signal with the digital received signal to generate an in-phase digital signal; mixing an orthogonal signal with the received signal to generate an orthogonal digital signal, wherein the frequency of the in-phase signal and the orthogonal signal is the particular frequency; performing addition integration on the in-phase digital signal to generate an in-phase integration signal; performing addition integration on the orthogonal digital signal to generate an orthogonal integration signal; and calculating the root mean square of the sum of the square of the in-phase integration signal and the square of the orthogonal integration signal to obtain the strength of signal corresponding to the particular frequency.
 4. The method of claim 3, wherein the frequency of the analog-to-digital conversion corresponds to the particular frequency.
 5. The method of claim 1, wherein the step of calculating the strength of a signal corresponding to a particular frequency of the plurality of frequencies further includes: performing analog-to-digital conversion on the received signal to produce a digital received signal; and performing Fourier transform on the digital received signal to generate the signal strength corresponding to each frequency of the plurality of frequencies.
 6. The method of claim 1, wherein the step of calculating the total signal strength of the electrical signal received by each of the first electrodes and second electrodes further includes: calculating the total signal strength of the electrical signal received by each first electrode; calculating the signal strength corresponding to each of the plurality of frequencies based on the electrical signal received by at least one first electrode to obtain a set of frequencies mixed by the transmitter; and calculating the total signal strength of all the frequencies in the set of frequencies in the electrical signal received by the second electrode.
 7. The method of claim 6, wherein a signal strength corresponding to each frequency in the set of frequencies is greater than a threshold.
 8. The method of claim 1, wherein the total signal strength of the electrical signal received by a particular second electrode is calculated while calculating the total signal strength of the electrical signal received by a particular first electrode.
 9. The method of claim 1, wherein the transmitter transmits the electrical signal according to a transmitter status, and the method further includes calculating the transmitter status based on information of the electrical signal.
 10. The method of claim 9, wherein calculating the transmitter status is based on one or any arbitrary combination of the following information of the electrical signal: the signal strength of a particular frequency in the plurality of frequencies mixed by the electrical signal; the total signal strength of the electrical signal; and the ratio of signal strengths of a first frequency to a second frequency in the plurality of frequencies mixed by the electrical signal.
 11. The method of claim 9, wherein the total signal strength of the electrical signal corresponds to the status of a sensor with n possible statuses in the transmitter.
 12. The method of claim 9, wherein the ratio of the signal strengths of the first frequency to the second frequency mixed by the electrical signal corresponds to the status of a sensor with n possible statuses in the transmitter.
 13. The method of claim 9, wherein the total signal strength of the electrical signal corresponds to the status of a first sensor with n possible statuses in the transmitter, wherein the ratio of signal strengths of the first frequency to the second frequency in the plurality of frequencies mixed by the electrical signal corresponds to the status of a second sensor with m possible statuses in the transmitter.
 14. The method of claim 9, wherein when the transmitter includes a plurality of sensors, the number of possible statuses of the transmitter status is the sum of the number of possible statuses of every one of the plurality of sensors.
 15. The method of claim 9, wherein when the transmitter includes a plurality of sensors, the transmitter status indication is one of arbitrary combinations of every sensor's status indication.
 16. A touch processing device for detecting a transmitter approximating or touching a touch sensitive device, the transmitter transmitting an electrical signal mixed by signals having a plurality of frequencies, the touch sensitive device including a plurality of first electrodes, a plurality of second electrodes and a plurality of sensing points intersected by those first and second electrodes, and the touch processing device being used for: calculating the strength of a signal corresponding to each of the plurality of frequencies in the electrical signal received by each of the first electrodes and second electrodes; summing all of the calculated strengths of signals corresponding to the plurality of frequencies; and calculating a relative position between the transmitter and the touch sensitive device according to the calculated total signal strengths.
 17. The touch processing device of claim 16, further comprising a demodulator for calculating the strength of a signal corresponding to a particular frequency of the plurality of frequencies, wherein the demodulator further includes: a signal generator for generating an in-phase signal and an orthogonal signal, wherein the frequency of the in-phase signal and the orthogonal signal is the particular frequency; at least a mixer for mixing the in-phase signal with the received signal to generate an in-phase analog signal, and mixing the orthogonal signal with the received signal to generate an orthogonal analog signal; at least an integrator for performing integration on the in-phase analog signal to generate an in-phase integration signal, and performing integration on the orthogonal analog signal to generate an orthogonal integration signal; at least a squarer for calculating the square of the in-phase integration signal and the square of the orthogonal integration signal; and at least a “Root Mean Square (RMS) of Sum” element for calculating the root mean square of the sum of the square of the in-phase integration signal and the square of the orthogonal integration signal to obtain the signal strength corresponding to the particular frequency.
 18. The touch processing device of claim 16, further comprising a demodulator for calculating the strength of a signal corresponding to a particular frequency of the plurality of frequencies, wherein the demodulator further includes: an analog-to-digital converter (ADC) for performing analog-to-digital conversion on the received signal to produce a digital received signal; a signal generator for generating an in-phase signal and an orthogonal signal, wherein the frequency of the in-phase signal and the orthogonal signal is the particular frequency; at least a mixer for mixing the in-phase signal with the digital received signal to generate an in-phase digital signal, and mixing the orthogonal signal with the digital received signal to generate an orthogonal digital signal; at least an addition integrator for performing addition integration on the in-phase digital signal to generate an in-phase integration signal, and performing integration on the orthogonal digital signal to generate an orthogonal integration signal; at least a squarer for calculating the square of the in-phase integration signal and the square of the orthogonal integration signal; and at least a “Root Mean Square (RMS) of Sum” element for calculating the root mean square of the sum of the square of the in-phase integration signal and the square of the orthogonal integration signal to obtain the signal strength corresponding to the particular frequency.
 19. The touch processing device of claim 18, wherein the frequency of the analog-to-digital conversion corresponds to the particular frequency.
 20. The touch processing device of claim 16, further comprising a demodulator for calculating the strength of a signal corresponding to each of the plurality of frequencies, wherein the demodulator further includes: an analog-to-digital converter (ADC) for performing analog-to-digital conversion on the received signal to produce a digital received signal; and a Fourier Transformer for performing Fourier Transform on the digital received signal to generate the signal strength corresponding to each of the plurality of frequencies.
 21. The touch processing device of claim 16, wherein the step of calculating the total signal strength of the electrical signal received by each of the first electrodes and second electrodes further includes: calculating the total signal strength of the electrical signal received by each first electrode; calculating the signal strength corresponding to each of the plurality of frequencies based on the electrical signal received by at least one first electrode to obtain a set of frequencies mixed by the transmitter; and calculating the total signal strength of all the frequencies in the set of frequencies in the electrical signal received by the second electrode.
 22. The touch processing device of claim 21, wherein a signal strength corresponding to each frequency in the set of frequencies is greater than a threshold.
 23. The touch processing device of claim 16, wherein the total signal strength of the electrical signal received by a particular second electrode is calculated while calculating the total signal strength of the electrical signal received by a particular first electrode.
 24. The touch processing device of claim 16, wherein the transmitter transmits the electrical signal according to a transmitter status, and the touch processing device further includes calculating the transmitter status based on information of the electrical signal.
 25. The touch processing device of claim 24, wherein calculating the transmitter status is based on one or any arbitrary combination of the following information of the electrical signal: the signal strength of a particular frequency in the plurality of frequencies mixed by the electrical signal; the total signal strength of the electrical signal; and the ratio of signal strengths of a first frequency to a second frequency in the plurality of frequencies mixed by the electrical signal.
 26. The touch processing device of claim 24, wherein the total signal strength of the electrical signal corresponds to the status of a sensor with n possible statuses in the transmitter.
 27. The touch processing device of claim 24, wherein the ratio of the signal strengths of the first frequency to the second frequency mixed by the electrical signal corresponds to the status of a sensor with n possible statuses in the transmitter.
 28. The touch processing device of claim 24, wherein the total signal strength of the electrical signal corresponds to the status of a first sensor with n possible statuses in the transmitter, wherein the ratio of signal strengths of the first frequency to the second frequency in the plurality of frequencies mixed by the electrical signal corresponds to the status of a second sensor with m possible statuses in the transmitter.
 29. The touch processing device of claim 24, wherein when the transmitter includes a plurality of sensors, the number of possible statuses of the transmitter status is the sum of the number of possible statuses of every one of the plurality of sensors.
 30. The touch processing device of claim 24, wherein when the transmitter includes a plurality of sensors, the transmitter status indication is one of arbitrary combinations of every sensor's status indication.
 31. A touch processing system for detecting a transmitter approximating or touching a touch sensitive device, the transmitter transmitting an electrical signal mixed by signals having a plurality of frequencies, the touch processing system comprising: the touch sensitive device including a plurality of first electrodes, a plurality of second electrodes and a plurality of sensing points intersected by those first and second electrodes; and a touch processing device for calculating the strength of a signal corresponding to each of the plurality of frequencies in the electrical signal received by each of the first electrodes and second electrodes, summing all of the calculated strengths of signals corresponding to the plurality of frequencies, and calculating a relative position between the transmitter and the touch sensitive device according to the calculated total signal strengths. 